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Algorithmically distinguishing irreducible characters of the symmetric group

2020/05/29 by Chow, Timothy Y., Paulhus, Jennifer
#05E10 (Primary) 20C30 (Secondary) #Combinatorics (math.CO) #FOS: Mathematics #Representation Theory (math.RT)

paper · doi:10.48550/arxiv.2006.00035

Abstract

Suppose that χλ and χμ are distinct irreducible characters of the symmetric group Sn. We give an algorithm that, in time polynomial in n, constructs π∈ Sn such that χλ(π) is provably different from χμ(π). In fact, we show a little more. Suppose f=χλ for some irreducible character χλ of Sn, but we do not know λ, and we are given only oracle access to f. We give an algorithm that determines λ, using a number of queries to f that is polynomial in n. Each query can be computed in time polynomial in n by someone who knows λ.

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